LAHORE, Pakistan (Reuters) -- A prominent anti-Taliban Pakistani Muslim cleric has been killed in a suicide bomb attack in the city of Lahore, police said.

In another blast at around the same time, a suicide car bomber set off explosives near a mosque in the northwestern town of Nowshera, killing at least three people, police said.

The blasts came as Pakistani forces stepped up attacks on militants across the northwest after the U.S. House of Representatives approved tripling aid to Pakistan to about $1.5 billion a year for the next five years.

Security forces have made progress in more than a month of fighting against Taliban militants in the Swat Valley, northwest of Islamabad, and in recent days have begun operations in several other parts of the region.

The militants have responded with a series of bomb attacks.

Moderate cleric Sarfraz Naeemi was attacked at his mosque complex just after leading Friday Prayers.

In Nowshera, in Northwest Frontier Province, three people were killed and more than 20 were wounded, police said.

Rising Islamist violence has raised fears for Pakistan's stability and for the safety of its nuclear arsenal but the offensive in Swat has reassured the United States about its commitment to the global campaign against militancy.

Pakistan is a vital security ally for the United States as it struggles to stabilize neighboring Afghanistan and defeat Al-Qaeda.

U.S. officials said on June 11 insurgent violence in Afghanistan had accelerated sharply alongside the arrival of new U.S. troops, reaching its highest level since 2001.

U.S. Central Intelligence Agency Director Leon Panetta said he believed Al-Qaeda leader Osama bin Laden was hiding in Pakistan and he hoped joint operations with Pakistani forces would find him.

Helicopters Attack

Police in Bannu, a town in Northwest Frontier Province adjacent to the North Waziristan militant stronghold on the Afghan border, said the military had fired artillery through the night at militant positions in the Jani Kheil area.

"Since sunrise, helicopter gunships have also been used in the attack. There have been reports of casualties on the militant side but we aren't sure how many," police official Sami Ullah told Reuters.

More than 130 militants have been killed in the fighting near Bannu this week up to June 11, according to military officers and a senior civilian official in the area.

Independent casualty estimates for the fighting in Bannu and other parts of the northwest are not available.

Gunship helicopters also attacked militants in the Bajaur and Mohmand regions on the Afghan border, both to the north of the city of Peshawar, military officials and residents said.

There has also been fighting this week in the South Waziristan and Orakzai ethnic-Pashtun tribal regions.

The military's chief spokesman was not available for comment but an analyst said the various air strikes appeared aimed at keeping militants bottled up.

"The operation in Swat has entered its final stages and troops are engaging militants elsewhere to stop them going to Swat and to disrupt their network," said Mahmood Shah, a former chief of security in the Pashtun tribal areas.

The U.S. House of Representatives approved tripling aid to Pakistan to about $1.5 billion a year for the next five years in a key part of a strategy to combat extremism with economic and social development.

The bill includes military aid with conditions that require the Obama administration to certify that Pakistan remains committed to fighting terrorist groups -- a provision that Pakistan had criticized.

The funding includes money for schools, the judicial system, parliament, and law enforcement agencies.

The fighting in Swat and other parts of the northwest has displaced about 2.5 million people and aid officials have appealed to donors to step up their help.